Ukrainian soldiers crossed into Russian territory Sunday, but Kiev said Monday they were forced there after running out of ammunition. Moscow is offering another version: The soldiers deserted the Ukrainian army.

Russia gave more than 400 Ukrainian soldiers safe passage into its territory overnight, and only 180 of them asked to be returned to Ukraine, Vasiliy Malayev, head of the border patrol in Russia’s Rostov region, told the Associated Press.

But a Ukrainian military spokesman, Oleksiy Dmitrashkovsky, denied that version of events. He told the AP that the troops, with Ukraine’s 72nd Brigade, were cornered into a position and came under fire from pro-Russia separatists who used tanks, mortars, artillery and missile launches for five hours. The attack forced the troops to splinter into two sections.

"One was meant to break out and join forces with a support unit. The other unit had the task of providing fire cover," Dmitrashkovsky said. "In doing that they fired their weapons until no ammunition remained, after which they abandoned their position and reached a place near a border crossing on Russian territory."